Synchronous Optical Network (SONET) is a standard for optical transport that has been formulated by the Exchange Carriers Standards Association (ECSA) for the American National Standards Institute (ANSI). ANSI sets industry standards in the United States for telecommunications and other industries. The International Telecommunications Union (ITU) has incorporated SONET into their Synchronous Digital Hierarchy recommendations.
The introduction of SONET has resulted in numerous benefits for network providers. First, data transmission rates up to 10 Gigabits per second (Gbit/s) are standardized in SONET systems. This makes SONET a suitable technology for network backbones, i.e., the “superhighways” of modern telecommunications networks. SONET also provides more efficient add/drop multiplexing (ADM) than pre-SONET systems. Additionally, with SONET, network providers can react quickly and easily to the requirements of their customers, e.g., leased lines can be switched in a matter of minutes. And, a network provider can use standardized network elements that can be controlled from a central location by means of a telecommunications management network.
Modern SONET systems include various automatic back-up and repair mechanisms to cope with system faults. Failure of a link or network element does not lead to the failure of the entire network. These back-up connections can also be monitored by a management system. Moreover, SONET is able to handle new, upcoming services such as video on demand and digital video broadcasting via asynchronous transfer mode (ATM). Finally, SONET supports gateways between different network providers and synchronous digital hierarchy (SDH). SONET interfaces are standardized. Thus, it is possible to combine network elements from different manufacturers into a network.
SONET defines optical carrier (OC) levels and the electrically equivalent synchronous transport signals (STS) for the fiber-optic based transmission hierarchy. For example, an OC-1 is equivalent to an STS-1 and provides a data transmission rate of 51.84 Mega bits per second (Mbps). Higher line rates are integer multiples of the base rate of 51.84 Mbps. In other words, an OC-3, and the corresponding STS-3, has a data transmission rate equal to 3 times 51.84 Mbps or 155.52 Mbps. Under the SONET standard, OC-3, OC-12, OC-48, and OC-192 are the most widely supported fiber-optic rates.
Existing SONET transport network analysis, i.e., design and planning methods and procedures (M & P), relies heavily on manual ad hoc approaches that are not adequate for complex metro networks and current evolving new technologies and market dynamics. Due to the recent increase in fiber connectivity in transport networks, the task of manual design of optimal SONET based ring networks is becoming complex and impractical.
Accordingly, there is a need for an improved system and method for analyzing and designing SONET transport networks.